It has been suggested that human postural sway reduces when a fingertip lightly touches a stable surface during quiet standing. However, the effect of light touch on body balance during walking has not been cleared, even though falling of elderly person is occurred during dynamic motion in daily life. Therefore, the present study aimed to assess whether or not the light touch on stable surface contributes to the enhancement of body balance during walking. Thirteen young subjects and 22 elderly subjects walked on the treadmill at the preference speed. They lightly touched a stable surface with the index fingertip during walking (LT condition). In addition, in young subject, the stabilizing effect of force touching condition (FT condition), in which they could forcefully touch the stable surface during walking, was investigated. The subjects also conducted normal walking (control condition). The results showed that the mean amplitude and standard deviation of acceleration of center of mass (CoMACC) in LT condition was significantly smaller than those in FT and control conditions in young subjects (p < 0.05). In addition, the CoMACC of elderly subjects was significantly reduced in LT condition (p < 0.05). Cross correlation (CCF) analysis revealed that there was a spatial-temporal relationship between CoMACC and second order differential of fingertip contact force in medial-lateral direction. These results indicate that the body balance during walking can be enhanced by the active light touch, via the proprioceptive and tactile information from upper limb.

DESCENTE SPORTS SCIENCE Vol.32/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE